1. Field of the Invention
This invention is directed in general to an assembly or arrangement for managing power distribution in a dual voltage electrical system.
2. Discussion of Related Art
In the past, power management in automotive vehicles has been based on fourteen volt (14V) electrical distribution systems. The emergence of new technologies has increased the demand for electrical power. Electrical content of vehicles is steadily growing due to electrical components, such as electric brakes and steering, performing the functions of previously mechanical components, and due to the addition of information and entertainment networks. Problems have arisen because of the two-to-three kilowatt maximum power limitation of current 14V alternators. Within the industry, proposals have been made to increase the electrical system voltage to forty-two volts (42V). In this way, higher power output can be obtained from the alternator without dramatically increasing the output current. However, it is too costly to immediately switch or redesign all existing electrical components to those that can handle 42V. So a transition period is foreseen by the industry wherein vehicles employ a dual voltage system including both 14V and 42V power supplies. Vehicles can thereby continue to use some of the present components. This will reduce costs and technical difficulties associated with the switchover from 14V to 42V.
U.S. Pat. No. 6,151,222 illustrates a dual voltage automotive electrical system circuit. The invention concentrates on the design of a DC/DC converter to power low voltage loads at a fixed conversion ratio. The converter protects itself against overload conditions and minimizes switching loss. In U.S. Pat. No. 5,643,693, a power distribution module is mounted on the top surface of a battery to provide a compact, component-consolidated module. The disclosure of U.S. Pat. No. 6,152,776 is directed in part to a connecting plate having busbars that electrically connect multiple batteries. Cylindrical batteries are inserted into a holder. The connecting plates engage the battery electrodes protruding from the ends of the holder. These patents do not appear to address the need for complete, effective power management for a dual voltage electrical system.
Accordingly, it is an object of this invention to provide an assembly that efficiently manages selective power distribution in a dual voltage vehicle electrical system.
Another object of the invention is to enable jump start aid for a dual voltage system from vehicles having either a dual or forty-two volt system or vehicles having a fourteen volt system only.
A further object of this invention is to join main electrical system elements at a single location in a compact design.
In carrying out this invention in the illustrative embodiment thereof, a power management busboard comprises a plurality of variously configured busbars positioned on a lower plate. The busbars have flat and cylindrical terminals extending upward from the plate and eyelet terminals positioned at different levels relative to the plate. An upper cover fits over the plate and has housings that at least partially enclose some of the flat and cylindrical terminals. The cover has openings through which others of the terminals extend. The cover has an area for accommodating three fourteen volt batteries joined in series to form a forty-two volt source. Terminals from the forty-two volt source connect with terminals of the busboard, such that forty-two volt power is directed along some of the busbars. Other busbar terminals electrically connect with a separate, single fourteen volt battery such that fourteen volt power is directed along other busbars of the busboard.
A relay mounted on the busboard connects the forty-two volt source with a vehicle starter. Two of the cover housings form jump start aid posts. One of the jump start aid posts provides 42V jump start capability. The other jump start aid post furnishes conventional 14V jump start capability. The 14V power from an aid vehicle is routed through a DC/DC converter that sets atop the 42V source. The converter converts the 14V power to 42V power to charge the batteries. Another housing includes a connection port for electrically connecting the busboard to a vehicle alternator. A terminal extending from a busbar connected to a fourteen volt port of the converter and a terminal extending from a busbar connected to the forty-two volt source provide electrical connection to a fourteen volt bus and a forty-two volt bus, respectively, of a junction box. The junction box is then able to distribute power to vehicle components having different voltage requirements.
The busboard, batteries, converter and junction box are secured within a power hub case with a lid having doors providing access to the jump start aid posts. The case is compact because of the way the elements fit together, and positions all the elements in a single location. The busboard straightforwardly supports and interfaces with the batteries, power relay and junction box. The provisions of fourteen volt jump aid and forty-two volt jump aid give jump start ability to a vehicle in case of drained batteries, regardless of the type of electrical system in the aiding vehicle. Snap-in interfaces between the busboard plate and cover, simple terminal insertion connection with batteries, and direct interfaces with the junction box provide easy and quick assembly.